Overload circuit breaker

ABSTRACT

An overload circuit breaker utilizes a stationary member having a first contact element located on its surface and a movable resilient member having a sacrificial contact element located on its surface. A resilient bimetallic member is operable as a toggle to control the movable member. An electrical terminal means is connected such that an electrical circuit is formed through the first and second contact elements as well as through the resilient bimetallic member and the movable resilient member. The movable resilient member moves with snap action from the first stable position to the second stable position upon a flow of a predetermined electrical current through the electrical circuit, thereby opening the first contact element and the sacrificial contact element and breaking the electrical circuit. The resilient bimetallic member operates from a single stable position to provide for automatic resetting of the circuit breaker. In some embodiments, an ambient temperature compensating element is provided, and in some, manual reset means are provided.

\ nited. States Patent 1 1 Summe et al.

[ June 28, 1974 OVERLOAD CIRCUIT BREAKER Primary Examiner-George Harris [76] 'lnventors: Richard 1). Summe, 5302 E. 72nd Emmer-Frd I p Indianapolis Ind 46250; Attorney, Agent, or FzrmHume, Clement, Brmks,

Everett 11. Vannoy, 500 Hillsdale ll/1111a", Olds & Cook, Ct., Indianapolis, Ind. 4690l 221 Filed: May 4, 1973 [57] STRACT An overload circuit breaker utilizes a stationary mem- [211 App]' 1 5 V ber having a first contact element located on its surface and a movable resilient member having a sacrifi- Remed Apphcam Data cial contact element located on its surface. A resilient Continuation-impart 0f 27L603, y 13, bimetallic member is operable as a toggle to control 1972- the movable member. An electrical terminal means is connected such that an electrical circuit is formed [52] US. Cl 337/101, 337/88, 337/343, through the first and second contact elements as well 337/345, 337/348 as through the resilient bimetallic member and the [51] llnt. Cl. ll-l0llh 61/00 movable resilient member. The movable resilient [58] Field of Search H 537/76 35 91 95, 101, member moves with snap action from the first stable 537/343, 345, 348,370 position to the second stable position upon a flow of a predetermined electrical current through the electrical circuit, thereby opening the first contact element and [56] References Cited the sacrificial contact element and breaking the elec- UNITED STATES PATENTS trical circuit. The resilient bimetallic member operates from a single stable position to provide for automatic 2,558,219 6/1951 K0111 337/343 x resetting of h cui eak In s em o me s, 2,910,561 10/1959 Frey et a1 337/88 an ambient temperature compensating element is pro- I vided, and in some, manual reset means are provided.

17 Claims, 13 Drawing Figures 8 3.9 IHl T \l llll /2 l! r 3 36 /6 li III i 24 7- l y- 1 -53 11% t gH\-f' 62 i I 11:: g p75 1 1 1 I I 22 H I 1 l/ J //lV l7 I9 52 72 74 400 40b -i 4 PATENTEDJUH281974 3,821; 8'79 sum 2 or a FIG.5 J

FIG. 8 w

1 OVERLOAD CIRCUIT BREAKER This is a continuation-in-part of our co-pending U.S. Pat. application Ser. No. 271,603, filed July 13, 1972.

BACKGROUND OF THE INVENTION The present invention relates to circuit breakers and ,more particularly, to electrical circuit breakers which are adapted to protect electronic appliances and the like.

In the field of electronics, it has been the general practice to employ eitherfuses or circuit breakers to perform the protective operation of protecting the apparatus or electronic circuit from an overload current condition. Although many of these devices perform satisfactorily, the delicacy of modern electronic circuitry, such as that found in television receivers and the like, requires a more accurate and dependable overload protective system.

Due to the high degree of heat generated in certain electrical applicances, difficulties have been encountered in the use of conventional circuit breakers where there is a failure to have incorporated therein a means for accurate ambient temperature compensation. While most electronic devices operate at room temperatures of 65-85 F., the ambient temperature of the environment can go as high as 150 F. Under these elevated ambient temperatures, unless the circuit breaker is properly compensated, the trip point of the breaker may be substantially shifted so that a false tripping or opening of the breaker contacts may occur. The present invention overcomes this difficulty.

It has also been found advantageous to utilize either a manually or an automatically resetable circuit breaker, especially when used in television receivers. The manually resetable circuit breaker such as that provided by the instant invention provides that the circuit may only be closed after the operator has removed his hand from the reset mechanism. This is exceptionally importantto provide operator protection and circuitry protection within the television receiver. The automatically resetable device provided by the present invention obviates the problem by eliminating the need for hand manipulation.

Heretofore, several prior art circuit breakers have been devised to overcome these problems. However, these prior art circuit breakers have not proved satisfactory under all conditions of service. One such prior art circuit breaker is described in U.S. Pat. No. 2,910,561, issued to C. F. Frey et al. on Oct. 27, 1959. The circuit breaker described in the Frey patent has not proved entirely satisfactory since under conditions of high current, such as 50 amps, the bimetal element 2d would anneal due to its relatively small dimensions. In addition, under conditions of approximately 150 amps the elements of the circuit breaker would split apart and float within the housing thereby creating the danger of uncontrolled short circuits. Furthermore, any accidental impact on the reset button 40 would tend to distort the housing as well as the member 1141 thereby inadvertently changing the break point for the circuit breaker. An additional limitation in the Frey circuit breaker arises from the fact that as current through the circuit breaker increases, the pressure between the contacts decreases thereby giving rise to the possibility of an unacceptable performance of the circuit breaker just prior to the break point.

Two similar prior art circuit breakers are disclosed in U.S. Pat. Nos. 3,038,047 and 3,234,348, issued to J F. Marquis and F. B. Desio, respectively, on June 5, 1962 and Feb. 8, 1966. Each of these circuit breakers utilize a pair of latching contacts. These contacts are not advantageous since they are subject to pitting. It has been recognized that when the contacts become pitted, the break point for the circuit breaker changes. Furthermore, the pitting of the contacts prevents using a low ratio of break current to hold current. Lastly, under high current conditions, the switch member 111 of the Desio patent and the switch member 20 of the Marquis patent would tend to obtain a reverse bend and if the breaker were to fail, this reverse bend would tend to cause the circuit breaker to fail in a closed position rather than in an opened position.

A third type of prior art switch is disclosed in U.S. Pat. No. 2,558,219, issued to E. F. Kohl on June 26, 1951. In this switch, no current is passed through the toggle member 11 or through the C-spring 7. This switch is designed to momentarily make and break a switch contact. While this switch bears certain similarities to the invention disclosed below, its method of operation is entirely different.

SUMMARY OF THE INVENTION The general purpose of this invention is to provide an electrical circuit breaker which embraces all of the advantages of similarly employed circuit breakers and possesses none of the aforedescribed limitations. To attain this, the present invention contemplates several unique overload circuit breakers. Each of these circuit breakers employs'a bimetallic toggle member which ensures that the pressure between the contacts increases prior to the break point of the circuit breaker thereby ensuring greater reliability. In addition, each of the toggle members is designed so as to eliminate the possibility of being annealed under high current conditions. Furthermore, a sacrificial contact element is employed to overcome the possibility of the contact elements fusing or welding together. Lastly, some of the preferred embodiments of the invention provide for ambient temperature compensation.

It is, therefore, an object of the present invention to provide a circuit breaker wherein the contact pressure is increased prior to opening, which is accurately compensated for ambient temperature changes and which is not subjected to contact sticking or welding.

Another object is to provide a resetable overload circuit breaker wherein the circuit cannot be made while the reset spring or button is depressed.

A further object of the invention is to provide a circuit breaker which may be utilized as a controlled relay.

Still another object of the invention is to provide an overload circuit breaker which is simple in construction, and reliable in operation.

Another object is to provide an overload circuit breaker having automatic reset means.

A still further object is to provide a circuit breaker in which the contacts maintain firm pressure until the point of break, and then snap apart.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a first preferred embodiment of the invention showing the contacts in their normally closed position.

FIG. 2 is a top plan view of the toggle member used in the circuit breaker of FIG. 1.

FIG. 3 is a sectional view taken along the line 33 of FIG. 1.

FIG. 4 is a sectional view taken along the line 44 of FIG. 1.

FIG. 5 is a sectional view of the circuit breaker of FIG. I showing the contacts in their open position.

FIGS. 6 and 7 are diagrammatic views, with parts removed, of the circuit breaker of FIG. 1, showing the contacts in their closed position and open position, respectively.

FIG. 8 is a sectional view of a second preferred embodiment of the invention showing the contacts in their normally closed position.

FIG. 9 is a top plan view of the toggle member used in the circuit breaker of FIG. 8.

FIGS. 10 and 11 are diagrammatic views, with parts removed, of the circuit breaker of FIG. 8, showing the contacts in their closed and open position, respectively.

FIG. 12 is a diagrammatic view of one of the circuit breakers of the present invention being utilized as a controlled relay. I

FIG. 13 is a sectional view taken along the lines l3l3 of FIG. 12. A

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIGS. 1-4 an overload circuit breaker 10 which illustrates a first embodiment of the invention. The overload circuit breaker 10 includes a stationary member 12 which has a first end 14 and a second end 16. In the preferred embodiment, the stationary member 12 is substantially planar and is manufactured from any suitable conducting material. The first end 14 of the stationary member 12 is connected to an insulator 18 in a conventional manner. As will become evident below, the insulator 18 may comprise a single insulator having slots therein to accept the various members or may comprise a plurality of insulators which are fastened together by a suitable fastening means 17. Located on the surface of the stationary member 12 is contact element 20. The contact element 20, in the preferred embodiment, may comprise any suitable conducting material and may be integral with the stationary member 12 or may be affixed thereto in conventional manner.

The overload circuit breaker 10 further comprises a resilient member 22 having a first end 24 and a second end 26. The first end 24 of the resilient member 22 is secured within the insulator l8 and is spaced apart from the stationary member 12. A sacrificial contact element 36 is located on the upper surface of the resilient member 22. In the preferred embodiment, the contact elember 36 is embossed on the surface of the resilient member 22.

Resilient member 22 is manufactured from a metal having conventional current carrying capability for normal currents. However, the melting point and thermal conductivity of the metal and the shape of the emboss (element 36) are such that under large current surges, the high current density will cause element 36 to become molten in the area where it contacts element 20. Because the contact element 36 becomes molten at high current levels, the contact element 36 will not become welded nor will it fuse to the other contact element 20. This type of contact is known as a sacrificial contact.

The overload circuit breaker 10 further comprises a resilient bimetallic toggle member 50. As can be seen from FIG. 2, the resilient bimetallic toggle member 50 comprises a first leg 54 and a second leg 56. The first and second legs 54 and 56 are electrically connected at the second end 58 of the resilient bimetallic toggle member 50. However, the first leg 54 and the second leg 56 are not electrically connected at the first end 57 of the bimetallic toggle member 50. The bottom surface 52 of the bimetallic resilient toggle member 50 comprises a high expansion side while the top surface 53 comprises a low expansion side. The resilient bimetallic toggle member 50 in the preferred embodiment comprises a relatively large cross-sectional and surface area. These large areas serve to dissipate heat which is caused by large current surges and also serve as a thermal reservoir thereby preventing circuit breaker 10 from being subject to false openings which might be caused by short duration transients which are not harmful to the circuit being protected.

As can be seen from FIGS. 1 and 3, the first leg 54 is placed in contact with the first end of the resilient member 22. The first end of the second leg 56 of the resilient bimetallic toggle member 50 is insulated from the resilient member 22 by an insulator 19. An electrical terminal means 40a which is part of stationary member 12 and an electrical terminal means 401) which is connected to the second leg 56 of the resilient bimetallic toggle member 50 are provided. An electrical circuit is, therefore, formed through the terminal means 40b, through the second leg 56 of the bimetallic toggle member 50, through the first leg 54 of the bimetallic toggle member 50, through the resilient member 22, the contact elements 36, 20, and finally out through the stationary member 12 and the terminal means 40a.

Referring again to FIG. I, a resilient C-spring is mounted between the second end 26 of the resilient member 22 and the end 58 of the resilient bimetallic toggle member 50. The C-spring 60 is provided to maintain the resilient bimetallic toggle member 50 in a first stable position and to maintain the resilient member 22 in a first stable position as shown in FIG. 1.

' When the resilient bimetallic toggle member 50 and the resilient member 22 are in their first stable position, the contact elements 20 and 36 are closed. The C-spring 60 may be made from any resilient material and it will be recognized that its shape may be changed and need not necessarily comprise a C shape. The C-spring 60 is electrically insulated from the bimetallic toggle member 50 by an insulating member placed on the end 58. If ambient temperature compensation is desired in the circuit breaker 10, the C-spring 60 may be made from a bimetallic material and the high expanding side of the bimetallic material would be placed on the inner surface 62 of the C-spring 60. It should be noted that as the ambient temperature increases, the C-spring 60 will expand thereby counteracting the expansion of the bimetallic element 50 due to the increasing ambient temperature thereby eliminating the possibility of an inadvertent opening of the contact elements 28 and 36.

When the contact elements 28 and 36 are in their closed position, as shown in FIGS. I and 6, the bimetallic toggle member 58 is in its first stable position. If an overload current condition occurs, the bimetallic toggle member 58 would bend and move upward over center to a second stable position and the resilient member 22 would move downward with a snap action to a second stable position thereby compressing the C-spring 68 and causing the contact elements 28 and 36 to separate when the toggle member 58 goes over center as shown in FIGS. 5 and 7.

The bimetallic toggle member 58 reacts in this manner since during an overload condition, excessive heat is generated and this causes the high expansion side of the resilient bimetallic toggle member 58 to expand at a greater rate than the low expansion side of the resilient bimetallic toggle member 58, thereby causing the resilient bimetallic toggle member 58 to bend from its first stable condition to its second stable condition. It will be readily noted that as the high expansion side of the resilient bimetallic toggle member 58 expands, the pressure exerted between the contact elements 28 and 36 increases until the resilient bimetallic toggle member 58 and the resilient member 22 snap into their second stable positions thereby opening the contacts. The predetermined current level at which this snap action occurs is commonly referred to as the break point or set point for the circuit breaker.

The contact elements 28 and 36 remain separated until the resilient bimetallic toggle member 58 is returned to its first stable position. A reset element 38 is provided for this purpose. The reset element shown in FIG. I is adapted to move from a first position, as shown in FIG. I, to a second position. When it is desired to reset the overload circuit breaker I8, the reset element 38 is depressed downwardly to a second position. A pair of shoulders 39 (FIG. 4) on the reset element 38 contacts the legs 54 and 56 of the resilient bimetallic toggle member 58 causing the resilient bimetallic toggle member 58 to snap back to its first stable position thereby compressing the C-spring 68 and moving the second end 26 of the resilient member 22 up wardly thereby closing the contact elements 28 and 36. It will be noted that so long as the reset element 38 is depressed, the bridge 38a between the shoulders 39 will prevent the movable member 22 from snapping back to its first stable position and this will prevent the contact elements 28 and 36 from closing. When the reset element 38 is released, thereby enabling the reset element 38 to go back to its first position, the contact elements 28 and 36 will then close. By requiring the reset element 38 to return to its first position, prior to the closing of the contact elements 28 and 36, this as sures that the operator will not reclose the circuit until his hand has been removed thereby adding to the safety of the overload circuit breaker I8.

As can be seen in FIGS. I-S, the circuit breaker I8 further comprises a base member 78 upon which the resilient elements described above are mounted. The base member 78 comprises a conventional insulator material through which the terminal means 480 and 48b extend. An extension 72 is provided to serve as a stop for button 38 so that the resilient members are not damaged when button 38 is subjected to impact. Extension 72 also limits the downward travel of resilient member 22 when the contacts are open. Extension 72 further serves to hold resilient member 22 in a fixed position so that shoulders 39 on button 38 will push legs 54 and 56 of resilient bimetallic toggle member 58 over center will respect to the position of resilient member 22 and allow circuit breaker I8 to be reset. A pair of extensions 74 are provided to limit the downward travel of toggle member 58 and thereby assure that he contacts 36 and 28 remain closed when circuit breaker I8 is exposed to cold ambient temperatures.

Alternatively, automatic reset means may be provided and the manual reset element 38 dispensed with. In such a construction the bimetallic toggle member 58 is normally biased downwardly toward extensions 74, thereby maintaining the resilient member 22 in its first stable position as shown in FIG. 6. In response to heat generated by an overload current condition, the toggle 58 would bend upwardly against the normal bias, ultimately causing the resilient member 22 to snap downwardly to its second stable position, as shown in FIG. 7. Upon dissipation of the heat caused by the overload, the normal bias of the toggle 58 would again tend to urge it downwardly, eventually causing the member 22 to snap up into its first stable position, thus automatically resetting the unit.

Lastly, a housing 76 is placed over the base member 78 to protect the entire circuit breaker I8. It will be recognized that the overload circuit breaker 18, as well as the alternative circuit breaker described below, may be placed within any other suitably shaped housing and, furthermore, may also be utilized without a housing if it is so desired.

Referring now to FIGS. 8II, an overload circuit breaker I18 is shown which is similar to the overload circuit breaker I8. In this embodiment, a resilient bimetallic toggle member I58 FIG. 9) comprises a bimetallic construction having the high expanding side on the lower surface I52. A resilient member I22 is provided and is insulated from the toggle member I58 by an insulator II9. The resilient member I22 comprises a conductive material but is not bimetallic. A stationary member II2 is also provided. As before, a pair of contact elements I28 and I36 are provided on the lower surface of the stationary member II2 and the upper surface of the resilient element I22, respectively. A C-spring I68 is provided which maintains the contact elements I28 and I36 in their closed position. A pair of electrical terminals I48a and 14812 are connected respectively to the stationary member II2 and the resilient bimetallic toggle member I58. When the electrical terminals I48a and 114811 are connected to a source of current, an electrical circuit is provided through the resilient bimetallic toggle member I58, the conductive C-spring 168, the resilient member I22, the contact elements I36 and I28, and the stationary member II2.

As shown in FIGS. I8 and II, when the resilient bime tallic toggle member I58 is in its first stable condition, the contact elements I28 and I36 are closed. An overload of current flowing through the overload circuit breaker I118 would cause the resilient bimetallic toggle member I58 to move upward, thereby compressing the C-spring I68. When the C-spring I68 was compressed enough, the resilient bimetallic toggle member 158 would move over its center position and shift into a second stable position. The C-spring I68 would then push down the resilient member 122 thereby opening the contact elements 120 and 136. A reset element 138 is also provided to reset the contacts in a manner similar to that described above in connection with circuit breaker 10. Again, as in the case of the circuit breaker 10, automatic reset capability may be achieved by providing the toggle member 150 with a normal downward bias. As mentioned previously, the C-spring 160 may be made from any resilient material and it will be recognized that its shape may be changed and need not necessarily comprise a C shape.

If it is desired to compensate the overload circuit ,breaker 110 for changes in ambient temperature, the

C-spring 160 may utilize a bimetallic construction having the high expansion side along the upper surface 162. However, it will then be necessary to insulate the C-spring 160 by insulating members 175, from the bimetallic toggle member 150 and provide a flexible conductor 176 as a current bypass path. In this instance, a current path is provided from the terminals 140a and 14% through the resilient bimetallic toggle member 150, the flexible conductor 176, the resilient element 122, the contact elements 136 and 120, and the stationary member 112. The operation of the temperature compensation portion of the overload circuit breaker 110 will then be identical with that described above in connection with circuit breaker 10.

It is evident from the above construction that the operation of the circuit breaker 110 embodies the same advantage of the circuit breaker e.g., constantly increasing contact pressure prior to the break point, sacrificial contact element 136 to prevent welding, and relatively large cross-sectional and surface areas on toggle member 50 to prevent annealling by dissipating large amounts of heat which is caused by large current surges and also serve as a thermal reservoir preventing false openings due to short duration transients.

Referring now to FIG. 12, there is shown a relay control 210. It will be recognized that the relay control 210 is very similar to the overload circuit breaker 10 disclosed in FIGS. l-7. The relay control 210 comprises a stationary member 212 and a movable resilient member 222 which are connected via electrical terminals 280 and 281 to any electrical circuit. Located on the surface of the stationary member 212 is a Contact element 220 and similarly, a contact element 236 is located in the movable member 222. A toggle member 250 and a C-spring 260 are provided and serve the same function as their equivalent members shown in FIGS. l-7.

insulator 282 has been added between movable member 222 and first leg 254 of bimetallic toggle member 250. Electrical terminal 240a is placed in contact with the first leg 254. The second leg 256 of bimetallic toggle member 250 is insulated from electrical terminal 240a by insulator 219. Electrical terminal 240b is connected to second leg 256. The electrical circuit formed through terminal 240b, through the second leg 256 of bimetallic toggle member 250, through the first leg 254 of bimetallic toggle member 250, and finally out through terminal 2400 becomes the control circuit. if it is desired to open the contact elements 220 and 236, it'it only necessary to place a predetermined current through the control circuit which will then cause the resilient bimetallic toggle element 250 to move from its first stable position to its second stable position thereby opening the contacts 220 and 236.

Obviously, many modifications and variations of the present invention are possible in light of the above teaching and it should be understood that the foregoing disclosure relates only to preferred embodiments of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as set forth in the appended claims.

What is claimed is:

1. An overload circuit breaker comprising:

an insulating means;

a first resilient bimetallic member having a first leg and a second leg spaced apart from said first leg wherein said first leg and said second leg are elec trically insulated from each other at a first end and are electrically connected at a second end and wherein said first end is secured to said insulating means;

a snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is electrically connected to said first leg of said first bimetallic member;

a stationary conducting member having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said resilient conducting member;

a first contact element located on the surface of said stationary conducting member;

a second contact element located on the surface of said resilient conducting member;

a second resilient member connected between said second end of said first resilient bimetallic member and said second end of said resilient conducting member and electrically insulated therefrom wherein said second resilient member maintains said resilient conducting member in said first stable position whereby said first and second contact elements are electrically closed against each other; and

electrical terminal means connected to said second leg of said first resilient bimetallic member and connected to said stationary conducting member whereby when said first and second contact elements are closed against each other an electrical circuit is provided through said first resilient bimetallic member, said resilient conducting member, said first and second contact elements, and said stationary conducting member and whereby said resilient conducting member moves with a snap action to said second stable position upon a flow of a predetermined electrical current through said electrical circuit thereby opening said first and second contact elements and breaking said electrical circuit.

2. The overload circuit breaker of claim 1 wherein said second resilient member is bimetallic and acts as an ambient temperature compensating means.

3. The overload circuit breaker of claim 1 wherein said first resilient bimetallic member is biased to return said resilient conducting member to said first stable position upon dissipation of the heat generated by said flow of predetermined current, whereby said circuit breaker is automatically reset.

4. The overload circuit breaker of claim 1 including reset means actuable from a first position to a second position to cuase said resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position.

5. The circuit breaker of claim 1 wherein said second contact element comprises a sacrificial contact.

6. An overload circuit breaker comprising:

an insulating means;

a first resilient bimetallic member having a first end and a second end wherein said first end is secured to said insulating means;

a stationary conducting member having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from aid first resilient bimetallic member;

a first snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is secured to said insulat ing means and is spaced apart from said stationary conducting member;

a first contact element located on the surface of said stationary conducting member;

a second contact element located on the surface of said first resilient conducting member;

a second resilient conducting member connected between said second end of said first resilient bimetallic member and said second end of said first resilient conducting member wherein said second resilient conducting member maintains said first resilient conducting member in said first stable position whereby said first and said second contact elements are electrically closed against each other; and

electrical terminal means connected to said first resilient bimetallic member and connected to said stationary conducting member whereby when said first and second contact elements are closed against each other, an electrical circuit is provided through said first resilient bimetallic member, said second resilient conducting member, said second end of said first resilient conducting member, said first and second contact elements, and said stationary conducting member and whereby said first resilient conducting member moves with a snap action to said second stable position upon a flow of a predetermined electrical current through said electrical circuit thereby opening said first and second contact elements and breaking said electrical circuit.

7. The overload circuit breaker of claim 6 wherein said first resilient bimetallic member is biased to return said first resilient conducting member to said first stable position upon dissipation of the heat generated by said flow of predetermined current, whereby said circuit breaker is automatically reset.

8. The overload circuit breaker of claim 6 including reset means actuable from a first position to a second position to cause said first resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position.

9. The overload circuit breaker of claim 6 wherein I said second contact element comprises a sacrificial contact.

110. An overload circuit breaker comprising:

an insulating means;

a first resilient bimetallic member having a first end and a second end wherein said first end is secured to said insulating means;

a stationary conducting member having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said first resilient bimetallic member;

a snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said stationary conducting member;

a first contact element located on the surface of said stationary conducting member;

a second contact element located on the surface of said resilient conducting member;

a second resilient bimetallic member connected between said second end of said first resilient bimetallic member and said second end of said resilient conducting member and electrically insulated therefrom wherein said second resilient bimetallic member acts as an ambient temperature compensating means and maintains said resilient conducting member in said first stable position whereby said first and said second contact elements are electrically closed against each other;

flexible conductor means for electrically connecting said first resilient bimetallic member to said resilient conducting member; and

electrical terminal means connected to said first resilient bimetallic member and to said stationary conducting member whereby when said first and second contact elements are closed against each other an electrical circuit is provided through said first resilient bimetallic member, said flexible conductor means, said second end of said resilient member, said first and second contact elements, and said stationary conducting member and whereby said resilient conducting member moves with a snap action to said second stable position upon a flow of a predetermined electrical current through said electrical circuit thereby opening said first and second contact elements and breaking said electrical circuit.

ill. The overload circuit breaker of claim it) wherein said first resilient bimetallic member is biased to return said resilient conducting member to said first stable position upon dissipation of the heat generated by said flow of predetermined current, whereby said circuit breaker is automatically reset.

12. The overload circuit breaker of claim 10 including reset means actuable from a first position to a second position to cause said resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position.

13. The circuit breaker of claim 10 wherein said second contact element comprises a sacrificial contact.

M. A relay control for an electrical circuit comprismg:

a first, second and third insulating means;

a first resilient bimetallic member having a first leg and a second leg spaced apart from said first leg wherein said first leg and said second leg are electrically insulated from each other at a first end and are electrically connected at a second end;

a snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is electrically insulated from said first resilient bimetallic member by said first insulating means;

a stationary conducting member having a first end and a second end wherein said first end is secured to said second insulating means and is spaced apart from said resilient conducting member;

a first contact element located on the surface of said stationary conducting member;

a second contact element located on the surface of said resilient conducting member;

means for connecting said first and second contact elements to said electrical circuit;

a second resilient member connected between said second end of said first resilient bimetallic member and said second end of said resilient conducting member and electrically insulated therefrom wherein said second resilient member maintains said resilient conducting member in said first stable position whereby said first and second contact elements are electrically closed against each other;

first electrical terminal means connected to said first leg of said first bimetallic resilient member and insulated from said stationary conducting member by said first insulating means;

second electrical terminal means connected to said second leg of said first bimetallic resilient member and insulated from said first leg by said third insulating means whereby an electrical control signal applied to said first and second electrical terminal means generates heat in said first resilient bimetallic member and causes said first resilient bimetallic member to urge said resilient conducting member toward said second stable position thereby opening said first and second contact elements and breaking said electrical circuit.

15. The relay control of claim 14 wherein said second resilient member is bimetallic and acts as an ambient temperature compensating means.

16. The relay control of claim 14 wherein said first resilient bimetallic member is biased to return said resilient conducting member to said first stable position upon dissipation of said heat.

17. The relay control of claim 14 including reset means actuable from a first position to a second position to cause said resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means 

1. An overload circuit breaker comprising: an insulating means; a first resilient bimetallic member having a first leg and a second leg spaced apart from said first leg wherein said first leg and said second leg are electrically insulated from each other at a first end and are electrically connected at a second end and wherein said first end is secured to said insulating means; a snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is electrically connected to said first leg of said first bimetallic member; a stationary conducting member having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said resilient conducting member; a first contact element located on the surface of said stationary conducting member; a second contact element located on the surface of said resilient conducting member; a second resilient member connected between said second end of said first resilient bimetallic member and said second end of said resilient conducting member and electrically insulated therefrom wherein said second resilient member maintains said resilient conducting member in said first stable position whereby said first and second contact elements are electrically closed against each other; and electrical terminal means connected to said second leg of said first resilient bimetallic member and connected to said stationary conducting member whereby when said first and second contact elements are closed against each other an electrical circuit is provided through said first resilient bimetallic member, said resilient conducting member, said first and second contact elements, and said stationary conducting member and whereby Said resilient conducting member moves with a snap action to said second stable position upon a flow of a predetermined electrical current through said electrical circuit thereby opening said first and second contact elements and breaking said electrical circuit.
 2. The overload circuit breaker of claim 1 wherein said second resilient member is bimetallic and acts as an ambient temperature compensating means.
 3. The overload circuit breaker of claim 1 wherein said first resilient bimetallic member is biased to return said resilient conducting member to said first stable position upon dissipation of the heat generated by said flow of predetermined current, whereby said circuit breaker is automatically reset.
 4. The overload circuit breaker of claim 1 including reset means actuable from a first position to a second position to cuase said resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position.
 5. The circuit breaker of claim 1 wherein said second contact element comprises a sacrificial contact.
 6. An overload circuit breaker comprising: an insulating means; a first resilient bimetallic member having a first end and a second end wherein said first end is secured to said insulating means; a stationary conducting member having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from aid first resilient bimetallic member; a first snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said stationary conducting member; a first contact element located on the surface of said stationary conducting member; a second contact element located on the surface of said first resilient conducting member; a second resilient conducting member connected between said second end of said first resilient bimetallic member and said second end of said first resilient conducting member wherein said second resilient conducting member maintains said first resilient conducting member in said first stable position whereby said first and said second contact elements are electrically closed against each other; and electrical terminal means connected to said first resilient bimetallic member and connected to said stationary conducting member whereby when said first and second contact elements are closed against each other, an electrical circuit is provided through said first resilient bimetallic member, said second resilient conducting member, said second end of said first resilient conducting member, said first and second contact elements, and said stationary conducting member and whereby said first resilient conducting member moves with a snap action to said second stable position upon a flow of a predetermined electrical current through said electrical circuit thereby opening said first and second contact elements and breaking said electrical circuit.
 7. The overload circuit breaker of claim 6 wherein said first resilient bimetallic member is biased to return said first resilient conducting member to said first stable position upon dissipation of the heat generated by said flow of predetermined current, whereby said circuit breaker is automatically reset.
 8. The overload circuit breaker of claim 6 including reset means actuable from a first position to a second position to cause said first resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position.
 9. The overload circuit breaker of claim 6 wherein said second contact element comprises a sacrificial contact.
 10. An overload circuit breaker comprising: an insulating means; a first resilient bimetallic member having a firSt end and a second end wherein said first end is secured to said insulating means; a stationary conducting member having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said first resilient bimetallic member; a snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is secured to said insulating means and is spaced apart from said stationary conducting member; a first contact element located on the surface of said stationary conducting member; a second contact element located on the surface of said resilient conducting member; a second resilient bimetallic member connected between said second end of said first resilient bimetallic member and said second end of said resilient conducting member and electrically insulated therefrom wherein said second resilient bimetallic member acts as an ambient temperature compensating means and maintains said resilient conducting member in said first stable position whereby said first and said second contact elements are electrically closed against each other; flexible conductor means for electrically connecting said first resilient bimetallic member to said resilient conducting member; and electrical terminal means connected to said first resilient bimetallic member and to said stationary conducting member whereby when said first and second contact elements are closed against each other an electrical circuit is provided through said first resilient bimetallic member, said flexible conductor means, said second end of said resilient member, said first and second contact elements, and said stationary conducting member and whereby said resilient conducting member moves with a snap action to said second stable position upon a flow of a predetermined electrical current through said electrical circuit thereby opening said first and second contact elements and breaking said electrical circuit.
 11. The overload circuit breaker of claim 10 wherein said first resilient bimetallic member is biased to return said resilient conducting member to said first stable position upon dissipation of the heat generated by said flow of predetermined current, whereby said circuit breaker is automatically reset.
 12. The overload circuit breaker of claim 10 including reset means actuable from a first position to a second position to cause said resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position.
 13. The circuit breaker of claim 10 wherein said second contact element comprises a sacrificial contact.
 14. A relay control for an electrical circuit comprising: a first, second and third insulating means; a first resilient bimetallic member having a first leg and a second leg spaced apart from said first leg wherein said first leg and said second leg are electrically insulated from each other at a first end and are electrically connected at a second end; a snap action resilient conducting member operable between a first stable position and a second stable position and having a first end and a second end wherein said first end is electrically insulated from said first resilient bimetallic member by said first insulating means; a stationary conducting member having a first end and a second end wherein said first end is secured to said second insulating means and is spaced apart from said resilient conducting member; a first contact element located on the surface of said stationary conducting member; a second contact element located on the surface of said resilient conducting member; means for connecting said first and second contact elements to said electrical circuit; a second resilient member connected between said second end of said first resilient bimetallic member and said second end of said resilient conducting member and electrically insulated therefrom wherein said second resilient member maintains said resilient conducting member in said first stable position whereby said first and second contact elements are electrically closed against each other; first electrical terminal means connected to said first leg of said first bimetallic resilient member and insulated from said stationary conducting member by said first insulating means; second electrical terminal means connected to said second leg of said first bimetallic resilient member and insulated from said first leg by said third insulating means whereby an electrical control signal applied to said first and second electrical terminal means generates heat in said first resilient bimetallic member and causes said first resilient bimetallic member to urge said resilient conducting member toward said second stable position thereby opening said first and second contact elements and breaking said electrical circuit.
 15. The relay control of claim 14 wherein said second resilient member is bimetallic and acts as an ambient temperature compensating means.
 16. The relay control of claim 14 wherein said first resilient bimetallic member is biased to return said resilient conducting member to said first stable position upon dissipation of said heat.
 17. The relay control of claim 14 including reset means actuable from a first position to a second position to cause said resilient conducting member to move toward said first stable position while preventing said contact elements from closing until said reset means returns to said first position. 